Method and system for extracting and enriching micro-plastics in soft mud toys

Abstract

The invention provides a method and a system for extracting and enriching micro-plastics in ooze toys, and the method comprises the following steps: weighing an ooze toy sample, selecting a corresponding solvent to dissolve the sample according to the solubility of the ooze toys, water-soluble ultrapure water for the ooze toys, fat-soluble isopropanol for the ooze toys, water-soluble ultrapure water for the ooze toys, water-soluble isopropanol for the ooze toys, water-soluble ultrapure water for the ooze toys and water-soluble isopropanol for the ooze toys; then carrying out ultrasonic treatment until the sample is completely dissolved; carrying out suction filtration on the dissolved sample by using a filter membrane, washing a container containing the sample twice by using a corresponding dissolving solvent, transferring a washing solution into a suction filtration device, and carrying out combined suction filtration; washing the filter membrane with corresponding washing solvents in sequence, and taking out and drying the filter membrane after suction filtration is completed; putting the back surface of the dried filter membrane into a container, adding acetone, covering the container, performing ultrasonic treatment, taking out the filter membrane, and replacing the filter membrane with a clean glass beaker; and combining the extracted solvents, transferring the combined solvents into a centrifugal tube, centrifuging, sucking an upper-layer solution by using a glass suction tube under the condition of not disturbing a lower layer, and volatilizing the residual solvents to complete the extraction and enrichment of the micro-plastics in the soft mud toys. The method is high in reliability, and the micro-plastic content of the commercially available soft mud toys can be accurately detected.

Description

Technical Field

[0001] This invention relates to the extraction and enrichment of microplastics, specifically to a method and system for the extraction and enrichment of microplastics in slime-like toys. Background Technology

[0002] The healthy growth of children is crucial to the happiness of countless families, the expectations of society, and even the future of the nation. The potential threat of microplastics to children's health has become a critical issue that urgently needs attention. Microplastics typically refer to plastic particles with a diameter of less than 5 mm, encompassing both primary microplastics from industrial production and secondary microplastics generated from the degradation of plastics in the environment. As research has deepened, it has been proven that microplastics can have adverse effects on the health of organisms, including humans. Furthermore, due to their unique physiological characteristics, children are at significantly higher risk of microplastic harm than adults.

[0003] To control microplastic pollution, relevant policies and regulations have been introduced both domestically and internationally: In January 2020, my country's National Development and Reform Commission and the Ministry of Ecology and Environment jointly issued the "Opinions on Further Strengthening the Governance of Plastic Pollution," which clearly requires a ban on the production of cosmetics containing plastic microbeads by the end of 2020 and a ban on the sale of cosmetics containing plastic microbeads by the end of 2022; In 2022, my country's Ministry of Ecology and Environment defined microplastics, along with persistent organic pollutants, endocrine disruptors, and antibiotics, as four new categories of pollutants; In 2023, the European Commission issued the REACH Regulation Amendment (EU) 2023 / 2055, adding restrictions on synthetic polymeric microplastics with a size ≤5mm to Annex XVII (List of Restricted Substances) of the REACH Regulation, prohibiting the intentional addition of such microplastics to products; In 2025, the EU's Rapid Alert System for Dangerous Products (RAPEX) for Non-Food Products announced three cases of toy product recalls, the reason for which was that the products contained excessive amounts of microplastics, which are environmentally toxic and may cause cancer or reproductive toxicity. It is particularly noteworthy that infants and young children have a habit of crawling and biting plastic toys, which exposes them to microplastics more often in their daily activities, further highlighting the urgency of controlling microplastics in toys.

[0004] Meanwhile, both domestic and international efforts are actively promoting the standardization of microplastic detection methods to achieve uniformity: the International Organization for Standardization (ISO) has released a series of standards focusing on the release detection of microplastic particles from fabric materials in simulated laboratory environments, the textile industry, and household washing scenarios; the American Society for Testing and Materials (ASTM) has issued five microplastic detection and testing methods for water samples with different suspended solids contents (high, medium, and low), systematically providing qualitative and quantitative technical solutions for microplastics in complex water bodies; and my country also released GB / T40146—2021 "Determination of Plastic Microbeads in Cosmetics" in 2021, clarifying the specific procedures for pretreatment and qualitative analysis (Fourier transform infrared spectroscopy and Fourier transform micro-infrared spectroscopy) of plastic microbeads in cosmetics.

[0005] However, slime toys, a collective term encompassing similar products such as crystal slime, liquid glass, and artificial water, possess unique matrix properties—significantly different from common matrices like soil, food, and cosmetics. This renders existing microplastic extraction methods for other matrices unsuitable. Currently, pretreatment methods (including extraction and enrichment stages) for microplastics in slime toys are lacking, severely hindering the qualitative and quantitative analysis of microplastics in these toys and subsequent safety management. Therefore, developing microplastic extraction and enrichment methods suitable for slime toys has significant practical importance and application value. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for extracting and enriching microplastics in slime-like toys.

[0007] The method for extracting and enriching microplastics in slime-like toys according to the present invention includes the following steps:

[0008] Step S1: Weigh the slime toy sample, select the appropriate solvent to dissolve the sample according to the solubility of the slime toy, and then perform ultrasonic treatment until the sample is completely dissolved;

[0009] Step S2: Use a filter membrane to filter the dissolved sample, and wash the container holding the sample twice with the corresponding dissolving solvent. Transfer the washing liquid to the filtration device and filter together.

[0010] Step S3: Wash the filter membrane sequentially with the corresponding washing solvent, remove the filter membrane and dry it after filtration is completed;

[0011] Step S4: Place the dried filter membrane in a container with the reverse side facing up, add acetone, cover the container, and then ultrasonically remove the filter membrane and replace it with a clean glass beaker. Repeat the above acetone ultrasonic operation several times.

[0012] Step S5: Combine the solvents obtained from multiple acetone ultrasonic extractions and transfer them to a centrifuge tube. After centrifugation, use a glass pipette to aspirate the upper layer solution without disturbing the lower layer, and evaporate the remaining solvent to complete the extraction and enrichment of microplastics from slime toys.

[0013] Preferably, the mass of the slime-like toy sample weighed in step S1 is 2.0–5.0 g; and the pore size of the filter membrane is 1 μm.

[0014] Preferably, the slime-like toy body is a water-soluble slime-like toy. In step S1, the corresponding dissolving solvent is ultrapure water, and the ultrasonic treatment conditions are ultrasonic time of 1-2 hours and water temperature of 40-60°C. If the sample is not fully dissolved, it needs to be placed at room temperature for 12-36 hours.

[0015] Preferably, the corresponding dissolving solvent used for washing the container in step S2 is ultrapure water; the corresponding washing solvents in step S3 are ultrapure water and ethanol, respectively.

[0016] Preferably, the slime-like toy body is a fat-soluble slime-like toy, and in step S1: the corresponding dissolving solvent is isopropanol, and the ultrasonic treatment conditions are ultrasonic time of 10-20 min and water temperature of 35-40℃.

[0017] Preferably, the corresponding dissolving solvent used for washing the container in step S2 is isopropanol; the corresponding washing solvents in step S3 are 20-50 mL of isopropanol and ethanol, respectively.

[0018] Preferably, in step S4: the ultrasound time is 5-10 minutes.

[0019] Repeat the above acetone ultrasound procedure multiple times, specifically repeating it twice, for a total of three acetone ultrasound procedures.

[0020] Preferably, in step S3, the filter membrane is dried naturally at room temperature or dried at 50-60°C (no additional drying reagent is required).

[0021] Preferably, in step S5, the solvent is evaporated by rotary evaporation or nitrogen blowing, and the evaporation temperature does not exceed 60°C.

[0022] The present invention provides a system for extracting and enriching microplastics in slime-like toys, comprising the following modules:

[0023] The sample dissolution and ultrasonic module is used to weigh the slime toy sample, select the appropriate solvent to dissolve the sample according to the solubility of the slime toy, and then perform ultrasonic treatment until the sample is completely dissolved.

[0024] The vacuum filtration and container washing module is used to filter the dissolved sample through the filter membrane and wash the container holding the sample twice with the corresponding dissolving solvent, and transfer the washing liquid to the vacuum filtration device for combined filtration.

[0025] The filter membrane washing and drying module is used to wash the filter membrane sequentially with the corresponding washing solvent, and after filtration, remove the filter membrane and dry it.

[0026] The acetone ultrasonic extraction module is used to place the dried filter membrane on the reverse side into a container, add acetone, cover the container, ultrasonically remove the filter membrane, and replace it with a clean glass beaker. The above acetone ultrasonic operation is repeated multiple times.

[0027] The solvent merging and evaporation module is used to merge the solvents after three acetone ultrasonic extractions, transfer them to centrifuge tubes, centrifuge them, and then use a glass pipette to aspirate the upper layer without disturbing the lower layer. The remaining solvent is then evaporated to complete the extraction and enrichment of microplastics from slime-like toys.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. This invention proposes for the first time a method for extracting and enriching microplastics in slime-like toys, filling the gap in microplastic pretreatment technology for this type of toy and providing key support for subsequent qualitative and quantitative analysis;

[0030] 2. This invention can effectively detect the microplastic content of commercially available slime toys, helping to control toy quality and compliance, and avoid recall risks. Spike verification shows that the microplastic recovery rate in both water-soluble and fat-soluble slime toys exceeds 80%, and the method has high extraction efficiency and strong reliability.

[0031] 3. This invention is designed with a specific process based on the solubility (water-soluble / fat-soluble) of toys, making it suitable for mainstream slime toys such as crystal slime, artificial water, and liquid glass, with a wide range of applications. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0033] Figure 1 This is a flowchart illustrating the steps of the method for extracting and enriching microplastics in slime-like toys in an embodiment of the present invention.

[0034] Figure 2 This is a sample image of crystal mud from an embodiment of the present invention;

[0035] Figure 3 This is a diagram showing the extraction and enrichment of microplastics in a crystal mud sample in an embodiment of the present invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be for both fixing and circuit connection purposes.

[0038] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] The present invention discloses a method for extracting and enriching microplastics in slime toys. It designs corresponding processing procedures for the differences in water solubility and fat solubility of slime toys. The present invention will be described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0041] Example 1

[0042] This embodiment is for water-soluble slime toys (such as crystal slime and artificial water), and the specific operation steps are as follows:

[0043] Step 1: Sample Weighing and Dissolving Preparation. Accurately weigh 2.0–5.0 g of crystal clay sample. See the sample condition section below. Figure 2 As shown, place it in a 500mL stoppered conical flask; measure 500mL of ultrapure water filtered through a 0.22μm glass fiber membrane and slowly add it to the conical flask, gently shaking to initially disperse the sample.

[0044] Step 2: Ultrasonic dissolution treatment. Place the stoppered conical flask containing the sample and ultrapure water into an ultrasonic device. Set the ultrasonic parameters: ultrasonic time 1-2 hours, water temperature controlled at 40-60℃. After ultrasonic treatment, observe the sample dissolution status. If the sample is not completely dissolved, place the conical flask at room temperature for 12-36 hours until the sample is completely dissolved and a homogeneous solution is formed.

[0045] Step 3: Vacuum filtration and container washing. Assemble the vacuum filtration apparatus, using a glass fiber membrane with a pore size of 1 μm as the filter medium. Slowly pour the completely dissolved sample solution from Step 2 into the vacuum filtration funnel and start the vacuum filtration apparatus for filtration. After the solution has been basically filtered, measure 100-200 mL of ultrapure water filtered through a 0.22 μm glass fiber membrane twice and wash the inner wall of the conical flask in sequence (ensuring that the sample residue on the flask wall is completely transferred). Pour the two washing solutions into the vacuum filtration funnel and combine them for filtration.

[0046] Step 4: Membrane washing and drying. After vacuum filtration, keep the vacuum filtration equipment running. First, measure 100-200 mL of ultrapure water filtered through a 0.22 μm glass fiber membrane and slowly rinse the surface of the 1 μm glass fiber membrane to remove residual water-soluble matrix. Then, measure 100-200 mL of ethanol and rinse the membrane again to further remove impurities. After rinsing, turn off the vacuum filtration equipment, remove the glass fiber membrane, and dry it to constant weight using room temperature natural drying or 50-60℃ drying method.

[0047] Step 5: Acetone ultrasonic extraction. Take a 100mL clean glass beaker, place the dried glass fiber filter membrane with the reverse side facing up into the beaker, add 5mL of acetone to the beaker, and completely cover the mouth of the beaker with aluminum foil (to prevent acetone evaporation and contamination from external impurities); place the beaker in an ultrasonic device and sonicate for 5-10 minutes; after sonication, carefully remove the filter membrane and transfer it to another clean 100mL glass beaker. Repeat the above "add acetone-cover with aluminum foil-sonication" operation twice to ensure that the microplastics adsorbed on the filter membrane are completely extracted.

[0048] Step 6: Solvent Combining and Evaporation. All solvent from the three acetone ultrasonic extractions is transferred to a clean container, then to a centrifuge tube. After centrifugation, the upper layer is aspirated using a glass pipette without disturbing the lower layer. The solvent is then evaporated using rotary evaporation or nitrogen blowing (evaporation temperature not exceeding 60℃). The enriched microplastics are obtained after evaporation. See the image below for the enriched state. Figure 3 It can be used for subsequent qualitative and quantitative analysis of microplastics.

[0049] Example 2

[0050] This embodiment is for fat-soluble slime-like toys (such as liquid glass), and the specific operation steps are as follows:

[0051] Step 1: Sample weighing and dissolution preparation. Accurately weigh 2.0-5.0g of liquid glass sample and place it in a 50-100mL stoppered conical flask. Measure 20-50mL of isopropanol and add it to the conical flask. Gently shake the conical flask to ensure that the sample and isopropanol are in full contact.

[0052] Step 2: Ultrasonic dissolution treatment. Place the stoppered conical flask containing the sample and isopropanol into an ultrasonic device and set the ultrasonic parameters: ultrasonic time 10-20 min, water temperature controlled at 35-40℃. After ultrasonic treatment, observe the sample dissolution status to ensure that the sample is completely dissolved (lipid-soluble samples can dissolve quickly under these parameters without additional room temperature standing).

[0053] Step 3: Vacuum filtration and container washing. Assemble the vacuum filtration device, using a glass fiber filter membrane with a pore size of 1μm as the filter medium. Pour the completely dissolved sample solution from Step 2 into the vacuum filtration funnel and start the vacuum filtration device for filtration. After the solution has been filtered, measure 10-20mL of isopropanol twice and wash the inner wall of the conical flask in sequence. Pour the washing liquid into the vacuum filtration funnel and combine the two filtrations to ensure that the residual sample in the conical flask is completely transferred to the filter membrane.

[0054] Step 4: Membrane washing and drying. Keep the vacuum filtration equipment running. First, measure 20-50 mL of isopropanol and rinse the surface of the 1 μm glass fiber membrane to remove the residual lipid-soluble matrix on the membrane. Then, measure 20-50 mL of ethanol and rinse the membrane to remove isopropanol residue and impurities. After rinsing, turn off the vacuum filtration equipment, remove the membrane, and dry it to constant weight using room temperature natural drying or 50-60℃ drying method.

[0055] Step 5: Acetone ultrasonic extraction, the operation is the same as in Example 1. Take a 100mL clean glass beaker, put the dried filter membrane in with the reverse side facing up, add 5mL of acetone and cover the mouth of the beaker with aluminum foil, and sonicate for 5-10 minutes; replace the clean beaker and repeat the above operation twice to ensure complete extraction of microplastics.

[0056] Step 6: Solvent Combination and Evaporation. Combine the solvents from the three acetone extractions, transfer them to centrifuge tubes, and centrifuge. Then, use a glass pipette to aspirate the upper layer solution without disturbing the lower layer. Evaporate the solvent using rotary evaporation or nitrogen blowing (evaporation temperature not exceeding 60℃) to obtain enriched microplastics, which can be used for subsequent qualitative and quantitative analysis.

[0057] To verify the reliability of the method of the present invention, spiked recovery tests were conducted on water-soluble (crystal slime) and fat-soluble (liquid glass) slime toy samples: standard microplastic particles with a diameter of 500 μm were added to the samples, and the samples were treated according to the methods of Examples 1 and 2 above. The microplastic recovery rate was then measured. The results showed that the recovery rate of microplastics in both water-soluble and fat-soluble slime toys was above 80%, indicating that the method of the present invention can effectively extract and enrich microplastics in slime toys and has good stability.

[0058] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0059] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for extracting and enriching microplastics from slime-like toys, characterized in that, Includes the following steps: Step S1: Weigh the slime toy sample, select the appropriate solvent to dissolve the sample according to the solubility of the slime toy, and then perform ultrasonic treatment until the sample is completely dissolved; Step S2: Use a filter membrane to filter the dissolved sample, and wash the container holding the sample twice with the corresponding dissolving solvent. Transfer the washing liquid to the filtration device and filter together. Step S3: Wash the filter membrane sequentially with the corresponding washing solvent, remove the filter membrane and dry it after filtration is completed; Step S4: Place the dried filter membrane in a container with the reverse side facing up, add acetone, cover the container, and then ultrasonically remove the filter membrane and replace it with a clean glass beaker. Repeat the above acetone ultrasonic operation several times. Step S5: Combine the solvents obtained from multiple acetone ultrasonic extractions and transfer them to a centrifuge tube. After centrifugation, use a glass pipette to aspirate the upper layer solution without disturbing the lower layer, and evaporate the remaining solvent to complete the extraction and enrichment of microplastics from slime toys.

2. The method according to claim 1, characterized in that, The mass of the slime-like toy sample weighed in step S1 is 2.0–5.0 g; the pore size of the filter membrane is 1 μm.

3. The method according to claim 1, characterized in that, The slime-like toy is a water-soluble slime-like toy. In step S1, the corresponding dissolving solvent is ultrapure water, and the ultrasonic treatment conditions are ultrasonic time of 1-2 hours and water temperature of 40-60℃. If the sample is not fully dissolved, it needs to be placed at room temperature for 12-36 hours.

4. The method according to claim 3, characterized in that, In step S2, the corresponding dissolving solvent used for washing the container is ultrapure water; in step S3, the corresponding washing solvents are ultrapure water and ethanol, respectively.

5. The method according to claim 1, characterized in that, The slime-like toy is a fat-soluble slime-like toy. In step S1, the corresponding dissolving solvent is isopropanol, and the ultrasonic treatment conditions are ultrasonic time of 10-20 min and water temperature of 35-40℃.

6. The method according to claim 5, characterized in that, In step S2, the corresponding solvent used to dissolve the container is isopropanol; in step S3, the corresponding solvents for washing are 20-50 mL of isopropanol and ethanol, respectively.

7. The method according to claim 1, characterized in that, In step S4: the ultrasound time is 5-10 minutes. Repeat the above acetone ultrasound procedure multiple times, specifically repeating it twice, for a total of three acetone ultrasound procedures.

8. The method according to any one of claims 1 to 8, characterized in that, In step S3, the filter membrane is dried naturally at room temperature or at 50-60°C (no additional drying reagent is required).

9. The method according to any one of claims 1 to 8, characterized in that, In step S5, the solvent is evaporated by rotary evaporation or nitrogen blowing, and the evaporation temperature does not exceed 60°C.

10. A system for extracting and enriching microplastics from slime-like toys, characterized in that, Includes the following modules: The sample dissolution and ultrasonic module is used to weigh the slime toy sample, select the appropriate solvent to dissolve the sample according to the solubility of the slime toy, and then perform ultrasonic treatment until the sample is completely dissolved. The vacuum filtration and container washing module is used to filter the dissolved sample through the filter membrane and wash the container holding the sample twice with the corresponding dissolving solvent, and transfer the washing liquid to the vacuum filtration device for combined filtration. The filter membrane washing and drying module is used to wash the filter membrane sequentially with the corresponding washing solvent, and after filtration, remove the filter membrane and dry it. The acetone ultrasonic extraction module is used to place the dried filter membrane on the reverse side into a container, add acetone, cover the container, ultrasonically remove the filter membrane, and replace it with a clean glass beaker. The above acetone ultrasonic operation is repeated multiple times. The solvent merging and evaporation module is used to merge the solvents after three acetone ultrasonic extractions, transfer them to centrifuge tubes, centrifuge them, and then use a glass pipette to aspirate the upper layer without disturbing the lower layer. The remaining solvent is then evaporated to complete the extraction and enrichment of microplastics from slime-like toys.

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